Role of leptin in blood pressure regulation and arterial hypertension

Maternal high fat diet programs spatial learning and central leptin signaling in mouse offspring in a sex-specific manner

Environmental factors in early life have been demonstrated to increase the risk of neurodevelopmental disorders in offspring, especially the deficiency of the cognitive ability. Leptin has emerged as a key hormone that conveys information on energy stores, but there is growing appreciation that leptin signaling may also play an important role in neurodevelopment. The present study aimed to investigate whether maternal HFD exposure impairs the offspring learning and memory through the programming of central leptin system. We observed that hippocampus-dependent learning and memory were impaired in male but not female offspring from HFD-fed maternal ancestors (C57BL/6 mice), as assessed by novel object recognition and Morris water maze tests. Moreover, the chromatin immunoprecipitation results revealed the maternal HFD consumption led to the increasement in the binding of the histone marker H3K9me3 in male offspring, which mediates gene silencing in the leptin receptor promoter region. Furthermore, there was an increase in the expression of the histone methylase SUV39H1 in male but not female offspring, which regulates H3K9me3. Additionally, it has been observed that IL-6 and IL-1 also could lead to similar alternations when acting on cultured hippocampal neurons in vitro. Taken together, our data suggest that maternal HFD consumption influences male offspring hippocampal cognitive performance in a sex-specific manner, and central leptin signaling may serve as the cross-talk between maternal diet and cognitive impairment in offspring.

Baroreflex afferent function is a part of insights of Leptin-mediated blood pressure reduction and Leptin-resistance hypertension

The aim of this study is to verify the impact of Leptin in blood pressure (BP) regulation and Leptin-resistance in metabolic/neurogenic hypertension through baroreflex afferents and dysregulation. Artery BP/heart rate (HR) were measured while nodose (NG) microinjection of Leptin, membrane depolarization/inward current were obtained by whole-cell patch from NG neurons isolated from adult female rats. Baroreflex sensitivity (BRS) tested with PE/SNP, distribution/expression of Leptin/receptors in the NG/nucleus tractus solitary (NTS) examined using immumostaining and qRT-PCR, and serum concentrations of Leptin/NE measured by ELISA were observed in control and high fructose-drinking induced hypertension (HTN-HFD) rats. The results showed that BP was significantly/dose-dependently reduced by Leptin NG microinjection likely through direct excitation of female-specific subpopulation of Ah-type neurons showing a potent membrane depolarization/inward currents. Sex-specific distribution/expression of OB-Ra/OB-Rb in the NG were detected with estrogen-dependent manner, similar observations were also confirmed in the NTS. As expected, BRS was dramatically decreased in the presence of PE/SNP in both male and female rats except for the female with PE at given concentrations. Additionally, serum concentration of Leptin was elevated in HFD-HTN model rats of either sex with more obvious in females. Under hypertensive condition, the mean fluorescent density of OB-R and mRNA expression for OB-Ra/OB-Rb in the NG/NTS were significantly down-regulated. These results have demonstrated that Leptin play a role in dominant parasympathetic drive via baroreflex afferent activation to buffer Leptin-mediated sympathetic activation systemically and Leptin-resistance is an innegligible mechanism for metabolic/neurogenic hypertension through baroreflex afferent dysregulation.

Role of Perturbated Hemostasis in MASLD and Its Correlation with Adipokines

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it one of the most prevalent chronic liver disorders. MASLD encompasses a range of liver pathologies, from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) with inflammation, hepatocyte damage, and fibrosis. Interestingly, the liver exhibits close intercommunication with fatty tissue. In fact, adipose tissue could contribute to the etiology and advancement of MASLD, acting as an endocrine organ that releases several hormones and cytokines, with the adipokines assuming a pivotal role. The levels of adipokines in the blood are altered in people with MASLD, and recent research has shed light on the crucial role played by adipokines in regulating energy expenditure, inflammation, and fibrosis in MASLD. However, MASLD disease is a multifaceted condition that affects various aspects of health beyond liver function, including its impact on hemostasis. The alterations in coagulation mechanisms and endothelial and platelet functions may play a role in the increased vulnerability and severity of MASLD. Therefore, more attention is being given to imbalanced adipokines as causative agents in causing disturbances in hemostasis in MASLD. Metabolic inflammation and hepatic injury are fundamental components of MASLD, and the interrelation between these biological components and the hemostasis pathway is delineated by reciprocal influences, as well as the induction of alterations. Adipokines have the potential to serve as the shared elements within this complex interrelationship. The objective of this review is to thoroughly examine the existing scientific knowledge on the impairment of hemostasis in MASLD and its connection with adipokines, with the aim of enhancing our comprehension of the disease.

Follow-up of a randomized trial optimizing neonatal nutrition in preterm very low birthweight infants: growth, serum adipokines, renal function and blood pressure

OBJECTIVE

The primary objectives were to compare body mass index (BMI) Z-score (Z), systolic blood pressure (SBP), serum leptin:adiponectin (L:A) ratio and estimated glomerular filtration rate (eGFR) at ~3 years adjusted age between two arms of a randomized controlled trial (RCT) comparing two modes of human milk fortification for very low-birthweight infants in the neonatal intensive care unit.

STUDY DESIGN

Follow-up of RCT at 33-48 months.

RESULTS

Follow-up data are available in 82/120 infants. Infants in the experimental arm have anthropometric data consistent with central obesity and higher serum L:A ratio (sensitivity analysis adjusting for sex and using all available data), but have similar eGFR and SBP at follow-up compared with controls. Serum L:A ratio is strongly correlated with anthropometric measurements suggesting central obesity.

CONCLUSIONS

Infants in the experimental arm have central obesity and higher serum L:A ratio compared with controls. Notably, serum L:A ratio is strongly correlated with weight gain.

TRIAL REGISTRATION

This randomized controlled trial was registered at ClinicalTrials.gov NCT02372136.

Adipokines are possible risk markers for aortic stenosis requiring surgery

OBJECTIVES

Aortic stenosis (AS) is the most prevalent valvular heart disease among adults. The adipocyte-derived hormones, leptin and adiponectin, have profound metabolic actions. We examined whether these adipokines are independently associated with future aortic valve replacement (AVR).

DESIGN

In this longitudinal case-control study, we identified 336 cases who had undergone AVR due to AS, and who had previously participated in population-based health surveys. Two referents were matched to each case and leptin and adiponectin concentrations were analysed from stored baseline survey samples. Uni- and multivariable logistic regression analyses were used to estimate the risk of future AVR. An additional cohort was identified for validation including 106 cases with AVR and 212 matched referents.

RESULTS

Median age (interquartile range (IQR)) in years at survey was 59.9 (10.4) and at surgery 68.3 (12.7), and 48% were women. An elevated concentration of leptin was not associated with future AVR (odds ratio [95% confidence interval]) (1.10 [0.92-1.32]), although leptin was associated with a higher risk in patients with coronary artery disease (CAD) having more than 5 years between survey and AVR (1.41 [1.08-1.84]). Adiponectin was not associated with higher risk for future AVR (0.95 [0.82-1.11]), although after stratification for age, higher levels were associated with reduced risk for AVR in persons aged ≥60 years at surgery (0.79 [0.64-0.98]). In the validation study, leptin was associated with future AVR whereas adiponectin was not. None of the associations remained significant after adjustment for body mass index (BMI).

CONCLUSIONS

The adipokine leptin may promote the development of AS.

Exploration of plasma adiponectin, leptin, and COMT genotype on blood pressure among women who are post-menopause

Research suggests that adiponectin, leptin, and genetic polymorphisms such as catechol-O-methyltransferase (COMT) genotype may play an integral role in blood pressure status and thereby cardiovascular health. This is an area especially important for women who are post-menopause; however, the current literature investigating these associations is limited. This study was a cross-sectional secondary analysis of baseline data (N 237) from the Minnesota Green Tea Trial (MGTT). The current study explored the relationships between plasma adiponectin, leptin, and COMT genotype on blood pressure measures. Plasma adiponectin and leptin were obtained after an overnight fast of at least 10 h and were measured by the radioimmunoassay method. The relationships were analysed using multiple linear regression after adjusting for potential confounders. Effect modifications by age, body mass index (BMI) category, blood pressure category, antihypertensive medication use, and COMT genotype were also investigated. The majority of participants were non-Hispanic (97⋅9 %) and Caucasian (94⋅9 %). Mean (sd) age and BMI were 60⋅7 (5⋅0) years and 28⋅2 (2⋅9) kg/m2, respectively. After adjustment for confounding variables, neither plasma adiponectin, plasma leptin nor COMT genotype was associated with systolic or diastolic blood pressure measures. The results of stratified analyses also did not reveal any significant interactions or associations. Based on the findings of this study, which utilised more rigorous statistical methods than previous research, neither adiponectin, leptin nor COMT genotype play a role in blood pressure measures in women who are post-menopause.

Dietary carbohydrate quality index (CQI), cardio-metabolic risk factors and insulin resistance among adults with obesity

BACKGROUND

Metabolic syndrome (MetS), as a cluster of cardiometabolic risk factors, is a global public health concern due to its increasing prevalence. Considering the previous evidence of the association between carbohydrate quality and cardiometabolic risk factors, our study was aimed to evaluate any possible association between carbohydrate quality index (CQI) and cardiometabolic risk factors among obese adults.

METHODS

In this cross-sectional study, 336 apparently healthy individuals with obesity were participated. Dietary intake was assessed by a semi-quantitative Food Frequency Questionnaire (FFQ), including 168 food items validated for the Iranian population. CQI was calculated with three components of solid carbohydrates to total carbohydrates ratio, dietary fiber intake, and dietary glycemic index (GI). Body composition was determined by bioelectrical impedance analysis (BIA). Blood pressure was measured by sphygmomanometer and enzymatic methods were used to evaluate serum lipid, glucose, and insulin concentrations.

RESULTS

Subjects in the third quartile of CQI had significantly lower systolic blood pressure (SBP) (P = 0.03) and diastolic blood pressure (DBP) (P = 0.01). Participants in the higher quartiles of CQI had more intake of energy, carbohydrates, fat, saturated fatty acid (SFA), and mono-saturated fatty acid (MUFA) (P < 0.05). Moreover, the homeostasis model assessment of insulin resistance (HOMA-IR) was decreased in the second quartile of CQI [odds ratio (OR) = 0.146, P = 0.01) after adjustment for age, body mass index (BMI), sex, physical activity, socioeconomic status (SES) and energy intake.

CONCLUSION

According to our findings, a higher quality of dietary carbohydrates, determined by CQI, could be associated with a lower risk of hypertension.

Probiotics: functional food ingredients with the potential to reduce hypertension

Hypertension is an increasingly pressing public health concern across the globe. It can be triggered by a variety of factors such as age and diet, as well as the stress of modern life. The traditional treatment of hypertension includes calcium ion blockers, angiotensin II receptor inhibitors and β-receptor blockers, but these drugs have at least some side effects. Recent studies have revealed that intestinal flora plays a vital role in maintaining and promoting human health. This is due to the type and amount of probiotics present in the flora. Probiotics can reduce hypertension symptoms through four mechanisms: regulating vascular oxidative stress, producing short-chain fatty acids, restoring endothelial cell function, and reducing inflammation. It has been reported that certain functional foods, using probiotics as their raw material, can modify the composition of intestinal flora, thus regulating hypertension symptoms. Consequently, utilizing the probiotic function of probiotics in conjunction with the properties of functional foods to treat hypertension is a novel, side-effect-free treatment method. This study seeks to summarize the various factors that contribute to hypertension, the mechanism of probiotics in mitigating hypertension, and the fermented functional foods with probiotic strains, in order to provide a basis for the development of functional foods which utilize probiotics as their raw material and may have the potential to reduce hypertension.

Metabolic changes after surgical fat removal: A dose-response meta-analysis

BACKGROUND

Bariatric surgery averts obesity-induced insulin resistance and the metabolic syndrome. By contrast, surgical fat removal is considered merely an esthetic endeavor. The aim of this article was to establish whether surgical fat removal, similar to bariatric surgery, exerts measurable, lasting metabolic benefits.

METHODS

PubMed, Embase, and Scopus were searched using the Polyglot Search Translator to find studies examining quantitative expression of metabolic markers. Quality assessment was done using the MethodologicAl STandard for Epidemiological Research scale. The robust-error meta-regression model was employed for this synthesis.

RESULTS

Twenty-two studies with 493 participants were included. Insulin sensitivity improved gradually with a maximum reduction in fasting insulin and homeostatic model assessment for insulin resistance of 17 pmol/L and 1 point, respectively, at postoperative day 180. Peak metabolic benefits manifest as a reduction of 2 units in body mass index, 3 kg of fat mass, 5 cm of waist circumference, 15 µg/L of serum leptin, 0.75 pg/ml of tumor necrosis factor-alpha, 0.25 mmol/L of total cholesterol, and 3.5 mmHg of systolic and diastolic blood pressure that were observed at day 50 but were followed by a return to preoperative levels by day 180. Serum high-density lipoproteins peaked at 50 days post-surgery before falling below the baseline. No significant changes were observed in lean body mass, serum adiponectin, resistin, interleukin-6, C-reactive protein, triglyceride, low-density lipoproteins, free fatty acids, and fasting blood glucose.

CONCLUSION

Surgical fat removal exerts several metabolic benefits in the short term, but only improvements in insulin sensitivity last beyond 6 months.

Effects of Coffee Supplementation on Homocysteine and Leptin Levels: A Systematic Review and Meta-analysis of Clinical Trials

BACKGROUND

It has been reported that the consumption of antioxidant foods and beverages may benefit the development of cardiovascular risk factors. However, the impact of coffee consumption on some of these factors, such as homocysteine and leptin is controversial. Some clinical trials have suggested that coffee administration increases plasma total homocysteine levels, while others have found no significant changes in leptin concentrations.

OBJECTIVE

This study aimed to assess the effects of coffee supplementation on homocysteine and leptin concentrations in a meta-analysis of clinical trials.

METHODS

PubMed, Web of Science, Scopus, ClinicalTrials.gov, and Google Scholar databases were searched from inception to September 29, 2021. A fixed-effects model and the generic inverse variance weighting method were used for meta-analysis.

RESULTS

The meta-analysis demonstrated that coffee administration significantly increases homocysteine levels (WMD: 0.55 μmol/L, 95% CI: 0.17, 0.93, p = 0.005, I2 = 0%) but has no significant changes in leptin concentrations (WMD: 1.34 ng/mL, 95% CI: -0.78, 3.45, p = 0.21, I2 = 0%). Additionally, the sensitivity analysis was robust for both homocysteine and leptin levels.

CONCLUSION

The results of the present meta-analysis revealed that coffee supplementation raises serum homocysteine concentrations but has no effect on circulating leptin levels.

Association of rs1137101 with hypertension and type 2 diabetes mellitus of Mongolian and Han Chinese

BACKGROUND

Hypertension (HTN) and type 2 diabetes mellitus (T2DM) are often coincident, and each condition is considered a risk factor for the other. Both occur frequently in the Inner Mongolia region of China. The reasons for differences in risk between Han and Mongolian ethnic groups are not known. The LEPR gene and its polymorphism, rs1137101 (Gln223Arg), are both considered risk factors for HTN and T2DM, but any role of rs1137101 in the occurrence of HTN + T2DM remains unclear for Mongolian and Han populations in the Inner Mongolia region.

AIM

To investigate the relationship between rs1137101 and the occurrence of HTN with T2DM in Mongolian and Han populations in Inner Mongolia.

METHODS

A total of 2652 subjects of Han and Mongolian ethnic origins were enrolled in the current study, including 908 healthy controls, 1061 HTN patients and 683 HTN patients with T2DM.

RESULTS

The association between the rs1137101 polymorphism and HTN with T2DM was analyzed, and differences between Han and Mongolian individuals assessed. There was a significant correlation between rs1137101 and HTN (co-dominant, dominant, over-dominant and log-additive models) and HTN + T2DM (co-dominant, dominant, over-dominant and log-additive models) after adjustment for sex and age in individuals of Mongolian origin. rs1137101 was significantly associated with HTN (co-dominant, recessive and log-additive models) and HTN + T2DM (co-dominant, dominant, over-dominant and log-additive models) in the Han Chinese population.

CONCLUSION

Mongolian and Han subjects from Inner Mongolia with HTN who had rs1137101 were protected against the development of T2DM. Allele A has the opposite impact on the occurrence of HTN in Mongolian and Han Chinese populations.

Rhamnolipids Regulate Lipid Metabolism, Immune Response, and Gut Microbiota in Rats

Objectives

Gut microbes influence lipid metabolism and immune responses that are key features of metabolic disorders. This study examined effects of bacterial rhamnolipids (RLS) on lipid metabolism, immune response, and gut microbiota in rats.

Methods

Twenty-four Sprague-Dawley rats were randomly divided into three groups and gavage-fed for seven weeks with normal saline (NCO group), 50 mg/kg bw RLS (RLS1 group), and 100 mg/kg bw RLS (RLS2 group).

Results

Compared with those of the NCO group, the RLS1 and RLS2 groups showed significantly decreased fat weight, relative fat weight, and adipocyte size (P < 0.05). Furthermore, RLS1 and RLS2 significantly decreased concentrations of triglycerides, low-density lipoprotein-cholesterol, and non-esterified fatty acids and increased high-density lipoprotein-cholesterol levels (P < 0.05). However, the total cholesterol content among the three groups (P > 0.05) were not significantly different. Serum concentrations of interleukin-1β, interleukin-6, and tumor necrosis factor-α were significantly lower in the RLS2 group than those in the NCO group (P < 0.05). The relative mRNA expression of fatty acid synthase was significantly decreased, while those of carnitine palmitoyltransferase-1, carnitine palmitoyltransferase-2, and peroxisome proliferator-activated receptor-gamma coactivator-1α were significantly increased in the RLS2 group compared with those in the NCO group (P < 0.05). Moreover, the relative abundances of Lactobacillus, Roseburia, Ruminococcus-1, and Parabacteroides were significantly higher in the RLS2 group than those in the NCO group (P < 0.05).

Conclusion

Our findings suggest that RLS reduces fat deposition, inhibits inflammation, regulates intestinal flora, and promotes the proliferation of beneficial bacteria in rats.

Apelin expression deficiency in mice contributes to vascular stiffening by extracellular matrix remodeling of the aortic wall

Numerous recent studies have shown that in the continuum of cardiovascular diseases, the measurement of arterial stiffness has powerful predictive value in cardiovascular risk and mortality and that this value is independent of other conventional risk factors, such as age, cholesterol levels, diabetes, smoking, or average blood pressure. Vascular stiffening is often the main cause of arterial hypertension (AHT), which is common in the presence of obesity. However, the mechanisms leading to vascular stiffening, as well as preventive factors, remain unclear. The aim of the present study was to investigate the consequences of apelin deficiency on the vascular stiffening and wall remodeling of aorta in mice. This factor freed by visceral adipose tissue, is known for its homeostasic role in lipid and vascular metabolisms, or again in inflammation. We compared the level of metabolic markers, inflammation of white adipose tissue (WAT), and aortic wall remodeling from functional and structural approaches in apelin-deficient and wild-type (WT) mice. Apelin-deficient mice were generated by knockout of the apelin gene (APL-KO). From 8 mice by groups, aortic stiffness was analyzed by pulse wave velocity measurements and by characterizations of collagen and elastic fibers. Mann-Whitney statistical test determined the significant data (p < 5%) between groups. The APL-KO mice developed inflammation, which was associated with significant remodeling of visceral WAT, such as neutrophil elastase and cathepsin S expressions. In vitro, cathepsin S activity was detected in conditioned medium prepared from adipose tissue of the APL-KO mice, and cathepsin S activity induced high fragmentations of elastic fiber of wild-type aorta, suggesting that the WAT secretome could play a major role in vascular stiffening. In vivo, remodeling of the extracellular matrix (ECM), such as collagen accumulation and elastolysis, was observed in the aortic walls of the APL-KO mice, with the latter associated with high cathepsin S activity. In addition, pulse wave velocity (PWV) and AHT were increased in the APL-KO mice. The latter could explain aortic wall remodeling in the APL-KO mice. The absence of apelin expression, particularly in WAT, modified the adipocyte secretome and facilitated remodeling of the ECM of the aortic wall. Thus, elastolysis of elastic fibers and collagen accumulation contributed to vascular stiffening and AHT. Therefore, apelin expression could be a major element to preserve vascular homeostasis.

Pro- and anti-inflammatory adipokines are associated with cardiometabolic risk markers in Brazilian schoolchildren

Pro- and anti-inflammatory adipokines have been regarded as potential markers of obesity and cardiometabolic comorbidities. However, few studies have evaluated this association in children. We aimed to evaluate the relationship between adipokine concentrations and cardiometabolic risk markers in Brazilian schoolchildren. This was a cross-sectional study with 378 children aged 8-9 years from Viçosa, Minas Gerais, Brazil. We measured adipokines (leptin, retinol-binding protein 4, adiponectin, and chemerin) and cardiometabolic risk markers (fasting glucose, HOMA-IR, lipid profile, and blood pressure). Cardiometabolic risk markers were compared by quintiles of adipokines with linear regression adjusted for potential confounders. Leptin was positively associated with diastolic blood pressure (P = 0.03) and HOMA-IR (P = 0.01), and retinol-binding protein 4 was positively associated with total cholesterol (P = 0.04). Each standard deviation of leptin and retinol-binding protein 4 was associated to, respectively, a 0.1 (95%CI: 0.1; 0.2), 0.3 (95%CI: 0.1; 0.6), and 2.5 (95%CI: 0.1; 4.9) units increase in diastolic blood pressure, HOMA-IR, and total cholesterol. Adiponectin was negatively associated with diastolic blood pressure (P = 0.01) and HOMA-IR (P = 0.01), and chemerin was negatively associated with glucose (P = 0.001). Each standard deviation of adiponectin and chemerin was associated to, respectively, a -0.1 (95%CI: -0.2; -0.1), -0.2 (95%CI: -0.3; -0.1), and -1.2 (95%CI: -1.9; -0.5) units decrease in diastolic blood pressure, HOMA-IR, and glucose.Conclusion: Pro- and anti-inflammatory adipokines were positively and negatively associated with cardiometabolic risk markers, respectively, among schoolchildren, indicating this relationship may be identified at earlier ages. What is Known: • Although leptin, retinol-binding protein 4, and adiponectin are well-known adipokines, a consensus regarding their relationship with cardiometabolic risk markers, especially in schoolchildren, has not yet been reached. • Chemerin is an adipokine that has been studied recently. Yet, due to its dependence on the target cell type, its functions are still a controversial topic. What is New: • Leptin was positively associated with diastolic blood pressure and HOMA-IR, and retinol-binding protein 4 was positively associated with total cholesterol. • Adiponectin was negatively associated with diastolic blood pressure and HOMA-IR, and chemerin was negatively associated with glucose.

The New Kid on the Block: The Mechanisms of Action of Hyperleptinemia in Coronary Artery Disease and Atherosclerosis

Leptin is an adipocytokine that consists of 167 amino acids. It functions as a regulator of hunger and energy expenditure. Leptin loses its ability to carry out its physiological function at high serum levels, and many studies have associated this loss of function with the development of coronary artery disease (CAD). This literature review aims to outline the steps by which leptin leads to CAD and atherosclerosis. Two independent researchers extracted animal and human studies from PubMed and Google Scholar databases. We applied PubMed search builder options: pathology, pathophysiology, metabolism, and physiology to focus the search results. This study concluded that the mechanism by which leptin might lead to CAD via pressor and depressor effects on vascular tone, enhancing atherosclerotic plaques, and through numerous single nucleotide polymorphisms, the most common being that of the leptin receptor gene rs113701. 

Plasma Leptin and Blood Pressure Progression in Blacks: The Jackson Heart Study

[Figure: see text].

Ghrelin and adipokines: An overview of their physiological role, antimicrobial activity and impact on cardiovascular conditions

The human body has many different hormones that interact with each other and with other factors such as proteins, cell receptors and metabolites. There is still a limited understanding of some of the underlying biological mechanisms of some hormones. In the past decades, science and technology have made major advancements in regard to innovation and knowledge in fields such as medicine. However, some conditions are complex and have many variables that their full picture is still unclear, even though some of these conditions have an alarming rate of incidence and serious health consequences. Conditions such as type 2 diabetes, obesity, nonalcoholic liver disease (NAFLD), cancer in its different forms and even mental conditions, such as Alzheimer's disease, are some of the most common diseases in the 21st century. These conditions are relevant not only because of their high incidence on the general population, but also because of their severity. In this chapter, we present an overview of cardiovascular (CV) diseases. According to the World Health Organization (WHO), cardiovascular diseases, such as coronary artery disease (CAD), heart attack, cardiomyopathy and heart failure (among others), are the number one cause of death worldwide. In 2016, it was estimated that 17.9 million people died from CV diseases, representing more than 30% of all global deaths. Approximately 95% of people who died from CV diseases were so-called "premature deaths" because were referenced to individuals under the age of 70 years old. In this chapter we described some of the hormones that may have an impact on CV diseases, including ghrelin, a peptide that is mostly produced in the stomach, known to induce hunger. Ghrelin is linked to an increase in body fat, i.e., adipose tissue in animals. For this reason, we also included the adipokines leptin, adiponectin and resistin. The main objectives of this chapter are to present the state of the art knowledge concerning the mechanisms of each hormone relevant to CV diseases; to compile data and results that further elucidate the relevance of these peptides for several physiological events, conditions and diseases; and to discuss the metabolic impact of each hormone. We established connections between multiple peptides and the underlying condition/disease with tools such as STRING, referring to research using databases, such as UniProt, DisGeNET and Proteomics DB. Fig. 1 shows a network that summarizes the information presented in this chapter, which serves as a visual representation.

Effects of Caloric Restriction Diet on Arterial Hypertension and Endothelial Dysfunction

The most common manifestation of cardiovascular (CV) diseases is the presence of arterial hypertension (AH), which impacts on endothelial dysfunction. CV risk is associated with high values of systolic and diastolic blood pressure and depends on the presence of risk factors, both modifiable and not modifiable, such as overweight, obesity, physical exercise, smoking, age, family history, and gender. The main target organs affected by AH are the heart, brain, vessels, kidneys, and eye retina. AH onset can be counteracted or delayed by adopting a proper diet, characterized by a low saturated fat and sodium intake, a high fruit and vegetable intake, a moderate alcohol consumption, and achieving and maintaining over time the ideal body weight. In this review, we analyzed how a new nutritional approach, named caloric restriction diet (CRD), can provide a significant reduction in blood pressure values and an improvement of the endothelial dysfunction. In fact, CRD is able to counteract aging and delay the onset of CV and neurodegenerative diseases through the reduction of body fat mass, systolic and diastolic values, free radicals production, and oxidative stress. Currently, there are few studies on CRD effects in the long term, and it would be advisable to perform observational studies with longer follow-up.

Blood Pressure Changes in 1610 Subjects With and Without Antihypertensive Medication During Long-Term Fasting

Background

We investigated daily blood pressure (BP) changes during fasting periods ranging from 4 to 41 (10.0±3.8) days in a cohort of 1610 subjects, including 920 normotensive, 313 hypertensive nonmedicated, and 377 hypertensive medicated individuals.

Methods and Results

Subjects underwent a multidisciplinary fasting program with a daily intake of ≈250 kcal. Weight and stress scores decreased during fasting, and the well‐being index increased, documenting a good tolerability. BP mean values decreased from 126.2±18.6/81.4±11.0 to 119.7±15.9/77.6±9.8 mm Hg (mean change, −6.5/3.8 mm Hg). BP changes were larger for hypertensive nonmedicated subjects (>140/90 mm Hg) and reduced by 16.7/8.8 mm Hg. This reduction reached 24.7/13.1 mm Hg for hypertensive nonmedicated subjects (n=76) with the highest BP (>160/100 mm Hg). In the normotensive group, BP decreased moderately by 3.0/1.9 mm Hg. Interestingly, we documented an increase of 6.3/2.2 mm Hg in a subgroup of 69 female subjects with BP <100/60 mm Hg. In the hypertensive medicated group, although BP decreased from 134.6/86.0 to 127.3/81.3 mm Hg, medication was stopped in 23.6% of the subjects, whereas dosage was reduced in 43.5% and remained unchanged in 19.4%. The decrease in BP was larger in subjects fasting longer. Baseline metabolic parameters, such as body mass index and glucose levels, as well as age, can be used to predict the amplitude of the BP decrease during fasting with a machine learning model.

Conclusions

Long‐term fasting tends to decrease BP in subjects with elevated BP values. This effect persisted during the 4 days of stepwise food reintroduction, even when subjects stopped their antihypertensive medication.

Registration

URL: https://www.drks.de/drks_web/; Unique identifier: DRKS00010111.

Association between plasma leptin/adiponectin ratios with the extent and severity of coronary artery disease

Background

Leptin can have a direct effect on endothelial and vascular smooth muscle cells and high level of leptin is involved in the pathogenesis of atherosclerosis. This study aimed to determine the relationship between leptin/adiponectin (L/A) ratio and the extent and severity of coronary artery disease (CAD).

Methods

This case-control study was conducted in an educational hospital in Ilam, Iran from June 2014 to September 2015. Totally 300 participants including 150 patients with CAD (case group) and 150 healthy individuals (control group) were selected and their plasma leptin, adiponectin and leptin/adiponectin ratio was measured. The extent and severity of coronary artery disease were assayed based on the number of involved vessels and Gensini score (GS) and the relation between scores and L/A findings were compared between cases and controls.

Results

Totally, 300 participants including 150 (42.7% male), mean age 59.5 ± 11.4 years as cases and 150 (50.7% male), mean age 59.8 ± 10.7 as controls were analyzed. Plasma level of leptin and L/A ratio were higher in cases compared to controls, but level of adiponectin was significantly lower in CAD patients than the control group. More number of involved coronary vessels was significantly correlated to higher level of plasma leptin, L/A ratio and lower level of adiponectin among case group. Moreover, adiponectin was negatively and leptin or L/A ratio were positively correlated with number of involved vessels. 7.3% of cases had only one involved vessel, 42.7% had two involved vessels, and 50% of total patients had involved vessels and the mean ± SD of GS in the case group was 23.6 ± 6.9.

Conclusions

Plasma levels of leptin, and adiponectin can indicate the extent of coronary artery diseases but leptin may be a better marker of extent of CAD than either L/A ratio or adiponectin separately.

Adipokines: New Potential Therapeutic Target for Obesity and Metabolic, Rheumatic, and Cardiovascular Diseases

Besides its role as an energy storage organ, adipose tissue can be viewed as a dynamic and complex endocrine organ, which produces and secretes several adipokines, including hormones, cytokines, extracellular matrix (ECM) proteins, and growth and vasoactive factors. A wide body of evidence showed that adipokines play a critical role in various biological and physiological functions, among which feeding modulation, inflammatory and immune function, glucose and lipid metabolism, and blood pressure control. The aim of this review is to summarize the effects of several adipokines, including leptin, diponectin, resistin, chemerin, lipocalin-2 (LCN2), vaspin, omentin, follistatin-like 1 (FSTL1), secreted protein acidic and rich in cysteine (SPARC), secreted frizzled-related protein 5 (SFRP5), C1q/TNF-related proteins (CTRPs), family with sequence similarity to 19 member A5 (FAM19A5), wingless-type inducible signaling pathway protein-1 (WISP1), progranulin (PGRN), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, retinol binding protein 4 (RPB4), and plasminogen activator inhibitor-1 (PAI-1) in the regulation of insulin resistance and vascular function, as well as many aspects of inflammation and immunity and their potential role in managing obesity-associated diseases, including metabolic, osteoarticular, and cardiovascular diseases.

Leptin-induced increase in blood pressure and markers of endothelial activation during pregnancy in Sprague Dawley rats is prevented by resibufogenin, a marinobufagenin antagonist

Levels of leptin and marinobufagenin (MBG), a cardiotonic steroid, are elevated in the serum of women with pre-eclampsia. Besides this, leptin administration to pregnant rats increases systolic blood pressure (SBP), urinary protein excretion and serum markers of endothelial activation. The link between leptin and MBG is unknown and it is also unclear if leptin-induced increases in blood pressure and proteinuria in the pregnant rat could be prevented by an MBG antagonist. To ascertain this link, this study investigated the effect of resibufogenin (RBG), a marinobufagenin antagonist, on leptin-induced increases in blood pressure and proteinuria during pregnancy in rats. Four groups of Sprague-Dawley rats, aged 12 weeks, were given either normal saline (CONTROL) or 120 μg/kg/day of leptin (LEP), or 120 μg/kg/day of leptin+30 μg/kg/day of resibufogenin (L + RBG) or 30 μg/kg/day of resibufogenin (RBG) from Day 1-20 of pregnancy. Systolic blood pressure and urinary protein excretion (UPE) were measured during the study period. Animals were euthanized on day 21 of pregnancy and vascular cell adhesion molecule 1, (VCAM-1), soluble intracellular cell adhesion molecule 1 (sICAM-1), E-selectin and endothelin-1 (ET-1) were estimated in the serum. SBP, UPE, VCAM-1, sICAM-1 and ET-1 were significantly higher only in the LEP group when compared with those in CONT and in L + RBG and RBG groups. The prevention by RBG of leptin-induced increases in SBP, proteinuria, and endothelial activation during pregnancy seem to suggest a potential role for MBG in leptin-induced adverse effects on blood pressure, urinary protein excretion and endothelial activity during pregnancy in the rat.

Leptin levels are not affected by enalapril treatment after an uncomplicated myocardial infarction, but associate strongly with changes in fibrinolytic variables in men

Leptin, an adipocyte-derived hormone, is involved in the regulation of body weight and is associated with obesity-related complications, notably cardiovascular disease (CVD). A putative link between obesity and CVD could be induction of plasminogen activator inhibitor-1 (PAI-1) synthesis by leptin. In this study, we hypothesized that the beneficial effect of the angiotensin-converting enzyme inhibitor (ACE_i) enalapril on PAI-1 levels is mediated by effects on leptin levels. The association between leptin and components of the fibrinolytic system was evaluated in a non-prespecified post hoc analysis of a placebo-controlled randomized, double-blind trial where the effect of the ACE_i enalapril on fibrinolysis was tested. A total of 46 men and 37 women were randomized to treatment with enalapril or placebo after (median 12 months) an uncomplicated myocardial infarction. At baseline, the participants were stable and had no signs of congestive heart failure. Leptin and fibrinolytic variables (mass concentrations of PAI-1, tissue plasminogen activator (tPA) and tPA-PAI complex) were measured at baseline, and after 10 days, 6 months and 12 months. Enalapril treatment did not change leptin levels, which increased significantly during 1 year of follow-up (p = .007). Changes in leptin levels were strongly associated with changes of tPA mass (p = .001), tPA-PAI complex (p = .003) and of PAI-1 (p = .006) in men, but not in women. Leptin levels are not influenced by treatment with an ACE_i. In contrast, leptin associates strongly with changes in fibrinolytic variables notably with a sex difference, which could be of importance for obesity-related CVD.

Sex and Body Mass Index Modify the Association Between Leptin and Sodium Excretion: A Cross-sectional Study in an African Population

BACKGROUND

Renal sodium handling could be a potential mediator linking adipokines to hypertension. The aim of the study was to assess the relationship of leptin with urinary sodium excretion and proximal sodium reabsorption in humans.

METHODS

This cross-sectional study was conducted on participants of hypertensive families from the Seychelles Island. A split urine (daytime and nighttime) collection and plasma leptin were measured. Endogenous lithium clearance was used to assess proximal sodium reabsorption. Mixed multiple linear regression tests adjusted for confounding factors were used.

RESULTS

Three hundred and sixty-five participants (57% women) were included in this analysis. Leptin and adiponectin were higher in women (P < 0.001). Leptin was associated positively with daytime (coefficient [c]: 0.16, standard deviation (SD): 0.03, P < 0.001), nighttime urinary sodium excretion (c: 0.17, SD: 0.04), P < 0.01), daytime lithium clearance (c: 0.40, SD: 0.08, P < 0.001), and nighttime lithium clearance (c: 0.39, SD: 0.10, P < 0.001) after adjusting for sex. The association was lost or mitigated only when BMI was introduced in the model. When BMI was categorized in normal vs. overweight participant, leptin was associated with daytime and nighttime sodium excretion rates (c: 0.14, SD: 0.05, P = 0.011 and c: 0.22, SD: 0.07, P = 0.002, respectively) only in overweight participants.

CONCLUSION

Leptin is associated positively with daytime and nighttime sodium excretion and lithium clearance suggesting a natriuretic rather than a sodium retaining effect of leptin. Sex and body mass index (BMI) are major confounders in this association. These results highlight the importance of sex and obesity in our understanding of the relationships between leptin, blood pressure, and renal sodium handling.

Perivascular Adipocytes in Vascular Disease

Perivascular adipocytes residing in the vascular adventitia are recognized as distinct endocrine cells capable of responding to inflammatory stimuli and communicating with the sympathetic nervous system and adjacent blood vessel cells, thereby releasing adipocytokines and other signaling mediators to maintain vascular homeostasis. Perivascular adipocytes exhibit phenotypic heterogeneity (both white and brown adipocytes) and become dysfunctional in conditions, such as diet-induced obesity, thus promoting vascular inflammation, vasoconstriction, and smooth muscle cell proliferation to potentially contribute to the development of vascular diseases, such as atherosclerosis, hypertension, and aortic aneurysms. Although accumulating data have advanced our understanding of the role of perivascular adipocytes in modulating vascular function, their impact on vascular disease, particularly in humans, remains to be fully defined. This brief review will discuss the mechanisms whereby perivascular adipocytes regulate vascular disease, with a particular emphasis on recent findings and current limitations in the field of research.

Childhood adversity and mechanistic links to hypertension risk in adulthood

Adverse childhood experiences (ACEs), defined as traumatic events in childhood that range from various forms of abuse to household challenges and dysfunction, have devastating consequences on adult health. Epidemiological studies in humans and animal models of early life stress (ELS) have revealed a strong association and insight into the mechanistic link between ACEs and increased risk of cardiovascular disease (CVD). This review focuses on the mechanistic links of ACEs in humans and ELS in mice and rats to vasoactive factors and immune mediators associated with CVD and hypertension risk, as well as sex differences in these phenomena. Major topics of discussion in this review are as follows: (a) epidemiological associations between ACEs and CVD risk focusing on hypertension, (b) evidence for association of ACE exposures to immune-mediated and/or vasoactive pathways, (c) rodent models of ELS-induced hypertension risk, (d) proinflammatory mediators and vasoactive factors as mechanisms of ELS-induced hypertension risk. We also provide some overall conclusions and directions of further research. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

Altered Adipose Tissue DNA Methylation Status in Metabolic Syndrome: Relationships Between Global DNA Methylation and Specific Methylation at Adipogenic, Lipid Metabolism and Inflammatory Candidate Genes and Metabolic Variables

Metabolic syndrome (MetS) has been postulated to increase the risk for type 2 diabetes, cardiovascular disease and cancer. Adipose tissue (AT) plays an important role in metabolic homeostasis, and AT dysfunction has an active role in metabolic diseases. MetS is closely related to lifestyle and environmental factors. Epigenetics has emerged as an interesting landscape to evaluate the possible interconnection between AT and metabolic disease, since it can be modulated by environmental factors and metabolic status. The aim of this study was to determine whether MetS has an impact on the global DNA methylation pattern and the DNA methylation of several genes related to adipogenesis (PPARG, PPARA), lipid metabolism (RXRA, SREBF2, SREBF1, SCD, LPL, LXRb), and inflammation (LRP1 C3, LEP and TNF) in visceral adipose tissue. LPL and TNF DNA methylation values were significantly different in the control-case comparisons, with higher and lower methylation respectively in the MetS group. Negative correlations were found between global DNA methylation (measured by LINE-1 methylation levels) and the metabolic deterioration and glucose levels. There were associations among variables of MetS, BMI, and HOMA-IR with DNA methylation at several CpG positions for the studied genes. In particular, there was a strong positive association between serum triglyceride levels (TG) with PPARA and LPL methylation levels. TNF methylation was negatively associated with the metabolic worsening and could be an important factor in preventing MetS occurrence according to logistic regression analysis. Therefore, global DNA methylation and methylation at specific genes related to adipogenesis, lipid metabolism and inflammation are related to the etiology of MetS and might explain in part some of the features associated to metabolic disorders.

Plasma leptin level is positively associated with blood pressure measures independent of gender and BMI

Background: Since the introduction of leptin, many studies suggest an important role for this hormone in obesity-related hypertension. However, in non-obese patients, there are controversial results regarding the possible role of leptin in essential hypertension especially in both sexes and different groups of body mass index (BMI). We aimed to evaluate the association of leptin and hypertension in both female and male gender.Materials and Methods: This cross-sectional study was conducted, recruiting 80 essential hypertensive patients and 80 healthy normotensive volunteers using convenience sampling method. Subjects without history of diabetes mellitus, hyperlipidemia, smoking, thyroid disease and insulin or corticosteroid use were included in two groups of normotensive and hypertensive subjects who were matched for age, sex and BMI. Systolic and diastolic blood pressure (SBP and DBP), weight and height were measured for all subjects and a blood sample was obtained for measurement of leptin, fasting blood sugar and lipid profiles.Results: Leptin was significantly higher in hypertensive patients as compared to normotensive subjects in all study population and both male and female subgroups (p < 0.001). Statistically significant correlation was also found between leptin and both SBP and DBP in above-mentioned subgroups. In comparison of controlled and uncontrolled hypertensive patients, leptin was significantly higher in uncontrolled hypertensive patients (p < 0.001).Conclusion: Comparing two groups of hypertensive and normotensive subjects, leptin is found to be positively correlated with hypertension in both genders. Leptin level also tends to be higher in uncontrolled hypertensive patients which may indicate a possible role for leptin in mechanism of uncontrolled hypertension.

Problematic eating behaviours, changes in appetite, and weight gain in Major Depressive Disorder: The role of leptin

BACKGROUND

Appetite and weight changes are core symptoms of Major Depressive Disorder (MDD), and those with MDD are at increased risk of obesity, cardiovascular disease and metabolic disorders. Leptin promotes satiety, with leptin dysregulation and resistance noted in obesity. However, the role of leptin in weight changes in MDD is not established. This study investigates leptin levels in relation to appetite and weight changes and problematic eating behaviours in MDD.

METHODS

Plasma leptin levels, psychopathology and biometrics were compared between participants meeting DSM-5 diagnostic criteria for MDD (n = 63) and healthy controls (n = 60). Depressed participants were also sub-categorised according to increased, decreased or unchanged appetite and weight. The Dutch Eating Behaviour Questionnaire and Yale Food Addiction Scale were examined in a subset of participants with MDD.

RESULTS

Females with increased appetite/weight had higher leptin levels than those with stable or reduced appetite/weight, however males showed the opposite effect. Leptin levels were positively correlated with problematic eating behaviours. One quarter of the depressed subset, all females, met the Yale criteria for food addiction, approximately double the rates reported in general community samples.

LIMITATIONS

The study is limited by a cross sectional design and a small sample size in the subset analysis of eating behaviours.

CONCLUSIONS

The results provide new information about associations between leptin, sex-specific weight and appetite changes and problematic eating behaviours, which may be risk factors for cardiovascular and metabolic diseases in MDD, particularly in females. Future longitudinal research investigating leptin as a risk factor for weight gain in MDD is warranted, and may lead to early interventions aimed at preventing weight gain in at-risk individuals.

Non-alcoholic fatty liver disease and hypertension: coprevalent or correlated?

OBJECTIVE

To provide a comprehensive review summarizing the existing evidence on the association between nonalcoholic fatty liver disease (NAFLD) and hypertension (HT) independent of other components of metabolic syndrome.

METHODS

We searched the literature through Medline and the Cochrane Library for studies evaluating the relationship between hypertension and fatty liver disease.

RESULTS

Studies testing this association are limited, but agree that HT and fatty liver disease are inter-related independent of other components of the metabolic syndrome such as obesity and diabetes mellitus. Clinical evidence shows that NAFLD is associated with new-onset HT, whereas increased blood pressure is related to the development of fatty liver disease and the possible subsequent progression to liver fibrosis. Insulin resistance and activation of the renin-angiotensin-aldosterone system (RAAS) might provide potential pathophysiologic links between these clinical entities. Until further evidence is available, patients with HT should be meticulously evaluated and treated for fatty liver disease and vice versa. RAAS inhibitors have been tested in NAFLD, presenting a favorable profile by decreasing insulin resistance and fibrosis progression.

CONCLUSION

NAFLD and HT are associated independent of traditional cardiovascular risk factors. Insulin resistance appears to be the main linking mechanism. Although RAAS inhibitors are the most beneficial treatment option for HT in patients with NAFLD, randomized studies on the administration of these agents in HT patients with NAFDL are warranted to provide optimal treatment options in these high cardiovascular risk individuals.

High serum leptin level is associated with peripheral artery disease in adult peritoneal dialysis patients

Objective:

Peripheral artery disease (PAD) is associated with systemic atherosclerosis and indicates an increased risk of mortality in peritoneal dialysis (PD) patients. A high leptin level accelerates atherosclerosis in apoE-deficient mice. The purpose of this study was to examine the association of serum leptin level and PAD in adult PD patients.

Materials and Methods:

The clinical characteristics of sixty PD patients recruited from June 2015 to October 2016 were obtained. Serum leptin concentrations were determined. Ankle–brachial index (ABI) values were measured and those with a left or right ABI <0.9 were defined as the low ABI group.

Results:

Twenty of these 60 PD patients (33.3%) had diabetes mellitus and 32 patients (53.3%) had hypertension. Thirteen PD patients (21.7%) were in the low ABI group. Higher serum leptin (P = 0.002) and C-reactive protein (CRP, P < 0.001) levels were found in the low ABI group compared with those in the normal ABI group. More number of patients with diabetes (P = 0.015) and current smokers (P = 0.037) were noted in the low ABI group than in the normal ABI group. After adjustment for factors that were significantly associated with PAD in multivariate logistic regression analysis, each increase of 1 ng/mL in the serum leptin level (odds ratio [OR], 1.062; 95% confidence interval [CI], 1.014–1.114; P = 0.012) and each increase of 0.1 mg/dL in the serum CRP level (OR, 1.107; 95% CI, 1.011–1.211; P = 0.028) were found to be independent predictors of PAD in PD patients.

Conclusion:

Higher serum leptin and CRP levels correlated positively with the diagnosis of PAD in PD patients.

Yoga training modulates adipokines in adults with high-normal blood pressure and metabolic syndrome

Metabolic syndrome (MetS) is associated with diabetes mellitus and cardiovascular diseases. Our previous study indicated that people with MetS showed a decrease in waist circumference and a decreasing trend in blood pressure after 1-year yoga. This study investigated the effect of yoga on MetS people with high-normal blood pressure by exploring modulations in proinflammatory adipokines (leptin, chemerin, visfatin, and plasminogen activator inhibitor-1 or PAI-1) and an anti-inflammatory adipokine (adiponectin). A total of 97 Hong Kong Chinese individuals aged 57.6 ± 9.1 years with MetS and high-normal blood pressure were randomly assigned to control (n = 45) and yoga groups (n = 52). Participants in the control group were not given any intervention but were contacted monthly to monitor their health status. Participants in the yoga group underwent a yoga training program with three 1-hour yoga sessions weekly for 1 year. The participants' sera were harvested and assessed for adipokines. Generalized estimating equation (GEE) was used to examine the interaction effect between 1-year time (pre vs post), and intervention (control vs yoga). GEE analyses revealed significant interaction effects between 1-year time and yoga intervention for the decreases in leptin and chemerin and the increase in adiponectin concentration in the sera examined. These results demonstrated that 1-year yoga training decreased proinflammatory adipokines and increased anti-inflammatory adipokine in adults with MetS and high-normal blood pressure. These findings support the beneficial role of yoga in managing MetS by favorably modulating adipokines.

Hypertension, diabetes, atherosclerosis and NASH: Cause or consequence?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease worldwide and its prevalence is expected to continue rising. NAFLD has traditionally been considered a consequence of metabolic syndrome (MetS). However, the link between NAFLD and MetS components, especially type 2 diabetes mellitus (T2DM), hypertension (HTN), and cardiovascular disease (CVD) is more complex than previously thought. Indeed, the adverse effects of NAFLD extend far beyond the liver, with a large body of clinical evidence now suggesting that NAFLD may precede and/or promote the development of T2DM, HTN and atherosclerosis/CVD. The risk of developing these cardiometabolic diseases parallels the underlying severity of NAFLD. Accumulating evidence suggests that the presence and severity of NAFLD is associated with an increased risk of incident T2DM and HTN. Moreover, long-term prospective studies indicate that the presence and severity of NAFLD independently predicts fatal and nonfatal CVD events. In this review, we critically discuss the rapidly expanding body of clinical evidence that supports the existence of a bi-directional relationship between NAFLD and various components of MetS, particularly T2DM and HTN, as well as the current knowledge regarding a strong association between NAFLD and CVD morbidity and mortality. Finally, we discuss the most updated putative biological mechanisms through which NAFLD may contribute to the development of HTN, T2DM and CVD.

High Fat Diet Decreases Neuronal Activation in the Brain Induced by Resistin and Leptin

Resistin and leptin are adipokines which act in the brain to regulate metabolic and cardiovascular functions which in some instances are similar, suggesting activation of some common brain pathways. High-fat feeding can reduce the number of activated neurons observed following the central administration of leptin in animals, but the effects on resistin are unknown. The present work compared the distribution of neurons in the brain that are activated by centrally administered resistin, or leptin alone, and, in combination, in rats fed a high fat (HFD) compared to a normal chow diet (ND). Immunohistochemistry for the protein, Fos, was used as a marker of activated neurons. The key findings are (i) following resistin or leptin, either alone or combined, in rats fed the HFD, there were no significant increases in the number of activated neurons in the paraventricular and arcuate nuclei, and in the lateral hypothalamic area (LHA). This contrasted with observations in rats fed a normal chow diet; (ii) in the OVLT and MnPO of HFD rats there were significantly less activated neurons compared to ND following the combined administration of resistin and leptin; (iii) In the PAG, RVMM, and NTS of HFD rats there were significantly less activated neurons compared to ND following resistin. The results suggest that the sensitivity to resistin in the brain was reduced in rats fed a HFD. This has similarities with leptin but there were instances where there was reduced sensitivity to resistin with no significant effects following leptin. This suggests diet influences neuronal effects of resistin.

Acute effects of intravenous cocaine administration on serum concentrations of ghrelin, amylin, glucagon-like peptide-1, insulin, leptin and peptide YY and relationships with cardiorespiratory and subjective responses

BACKGROUND

Food intake and use of drugs of abuse like cocaine share common central and peripheral physiological pathways. Appetitive hormones play a major role in regulating food intake; however, little is known about the effects of acute cocaine administration on the blood concentrations of these hormones in cocaine users.

METHODS

We evaluated serum concentrations of six appetitive hormones: ghrelin (total and acyl-ghrelin), amylin, glucagon-like peptide-1 (GLP-1), insulin, leptin and peptide YY (PYY), as well as acute cardiorespiratory and subjective responses of 8 experienced cocaine users who received 25mg intravenous (IV) cocaine.

RESULTS

Serum concentrations of GLP-1 (p=0.014) and PYY (p=0.036) were significantly decreased one hour following IV cocaine administration; there was a trend towards a decrease for insulin (p=0.055) and amylin (p=0.063) concentrations, while no significant IV cocaine effect was observed for ghrelin (total or acyl-ghrelin) or leptin concentrations (p's≫>0.5). We also observed associations between hormone concentrations acutely affected by IV cocaine (GLP-1, PYY, insulin, amylin) and some cocaine-related cardiorespiratory and subjective responses (e.g., increased heart and respiratory rates; feeling high and anxious).

DISCUSSION

These findings show a significant effect of acute IV cocaine administration on some appetitive hormones and suggest potential associations between these hormones and cocaine-related cardiorespiratory and subjective responses. Additional research is needed to further investigate the potential mechanisms underlining these associations.

Pathophysiology and Potential Non-Pharmacologic Treatments of Obesity or Kidney Disease Associated Refractory Hypertension

PURPOSE OF REVIEW

The review assesses the role of non-pharmacologic therapy for obesity and chronic kidney disease (CKD) associated refractory hypertension (rf HTN).

RECENT FINDINGS

Hypertensive patients with markedly heightened sympathetic nervous system (SNS) activity are prone to develop refractory hypertension (rfHTN). Patients with obesity and chronic kidney disease (CKD)-associated HTN have particularly heightened SNS activity and are at high risk of rfHTN. The role of bariatric surgery is increasingly recognized in treatment of obesity. Current evidence advocates for a greater role of bariatric surgery in the management of obesity-associated HTN. In contrast, renal denervation does not appear have a role in the management of obesity or CKD-associated HTN. The role of baroreflex activation as adjunctive anti-hypertensive therapy remains to be defined.

Oxidative and inflammatory signals in obesity-associated vascular abnormalities

Obesity is associated with increased cardiovascular morbidity and mortality in part due to vascular abnormalities such as endothelial dysfunction and arterial stiffening. The hypertension and other health complications that arise from these vascular defects increase the risk of heart diseases and stroke. Prooxidant and proinflammatory signaling pathways as well as adipocyte-derived factors have emerged as critical mediators of obesity-associated vascular abnormalities. Designing treatments aimed specifically at improving the vascular dysfunction caused by obesity may provide an effective therapeutic approach to prevent the cardiovascular sequelae associated with excessive adiposity. In this review, we discuss the recent evidence supporting the role of oxidative stress and cytokines and inflammatory signals within the vasculature as well as the impact of the surrounding perivascular adipose tissue (PVAT) on the regulation of vascular function and arterial stiffening in obesity. In particular, we focus on the highly plastic nature of the vasculature in response to altered oxidant and inflammatory signaling and highlight how weight management can be an effective therapeutic approach to reduce the oxidative stress and inflammatory signaling and improve vascular function.

Cardiovascular consequences of metabolic syndrome

The metabolic syndrome (MetS) is defined as the concurrence of obesity-associated cardiovascular risk factors including abdominal obesity, impaired glucose tolerance, hypertriglyceridemia, decreased HDL cholesterol, and/or hypertension. Earlier conceptualizations of the MetS focused on insulin resistance as a core feature, and it is clearly coincident with the above list of features. Each component of the MetS is an independent risk factor for cardiovascular disease and the combination of these risk factors elevates rates and severity of cardiovascular disease, related to a spectrum of cardiovascular conditions including microvascular dysfunction, coronary atherosclerosis and calcification, cardiac dysfunction, myocardial infarction, and heart failure. While advances in understanding the etiology and consequences of this complex disorder have been made, the underlying pathophysiological mechanisms remain incompletely understood, and it is unclear how these concurrent risk factors conspire to produce the variety of obesity-associated adverse cardiovascular diseases. In this review, we highlight current knowledge regarding the pathophysiological consequences of obesity and the MetS on cardiovascular function and disease, including considerations of potential physiological and molecular mechanisms that may contribute to these adverse outcomes.

Inflammatory and Metabolic Syndrome Biomarker Analysis of Vascular Outcomes in End-stage Renal Disease

End-stage renal disease (ESRD) presents a complex syndrome in which inflammatory and metabolic processes contribute to disease progression and development of comorbid conditions. Over $1 trillion is spent globally on ESRD care. Plasma samples collected from 83 ESRD patients prior to hemodialysis were profiled for metabolic and inflammatory biomarker concentrations. Concentrations were compared between groups with and without history of stroke, acute coronary syndrome (ACS), congestive heart failure (CHF), and coronary artery disease (CAD). The 25 patients (30.1%) with history of stroke demonstrated decreased plasma interferon-γ levels (p = 0.042) and elevated plasma resistin, interleukin (IL)-1α, and leptin levels (p = 0.008, 0.021, 0.026, respectively) when compared with ESRD patients without history of stroke. The 14 patients (16.9%) with history of ACS demonstrated elevated plasma IL-6 levels (p = 0.040) when compared with ESRD patients without history of ACS. The 30 patients (36.1%) with history of CHF demonstrated decreased plasma leptin levels (p = 0.031) and elevated plasma IL-1β levels (p = 0.042) when compared with ESRD patients without history of CHF. Finally, the 39 patients (47.0%) with history of CAD demonstrated elevated plasma IL-1α levels (p = 0.049) when compared with ESRD patients without history of CAD. Plasma biomarker concentration disturbances were observed in ESRD patients with history of stroke, ACS, CHF, and CAD when compared with ESRD patients without such history. Proinflammatory biomarker elevations were seen in stroke, ACS, CHF and CAD, while adipocytokine aberrations were observed in both stroke and CHF. These studies demonstrate that biomarker profiling of vascular comorbidities in ESRD may provide useful diagnostic and prognostic information in the management of ESRD patients.

Leptin-Induced Endothelium-Independent Vasoconstriction in Thoracic Aorta and Pulmonary Artery of Spontaneously Hypertensive Rats: Role of Calcium Channels and Stores

Decreased leptin-induced endothelium-dependent vasodilation has been reported in spontaneously hypertensive rats (SHR). Here, we report leptin-induced vasoconstriction in endothelium-denuded pulmonary artery and thoracic aorta from SHR and sought to characterize calcium handling underlying these mechanisms. Vasoreactivity to leptin was evaluated on pulmonary artery and thoracic aorta rings from 18 weeks old male SHR with or without calcium free medium, caffeine + thapsigargin + carbonyl cyanide-4-trifluoromethoxyphenylhydrazone emptying intracellular calcium stores, nifedipine a voltage-gated calcium channel inhibitor, SKF-96365 a transient receptor potential cation channels (TRPC) inhibitor, wortmaninn, a phosphatidylinositide 3-kinases (PI3K) inhibitor, or PD98059 a mitogen-activated protein kinase kinase (MAPKK) inhibitor. Calcium imaging was performed on cultured vascular smooth muscle cells incubated with leptin in presence or not of wortmaninn or PD98059. Leptin induced vasoconstriction in denuded pulmonary artery and thoracic aorta from SHR. Response was abolished when intra- or extracellular calcium stores were emptied, after blocking TRPC or voltage-dependent calcium channels or when using MAPKK or PI3K inhibitors. In vascular smooth muscle cells, leptin increased intracellular calcium. This rise was higher in SHR and abolished by MAPKK or PI3K inhibitors. TRPC6 gene expression was upregulated in arteries from SHR. Leptin-induced vasoconstriction in denuded arteries of SHR requires intracellular stores and is TRPC- and voltage-gated calcium channels dependent. Intracellular calcium increase is more pronounced in spontaneously hypertensive rats.

Pathophysiological Role of Adiponectin, Leptin and Asymmetric Dimethylarginine in the Process of Atherosclerosis

Adipose tissue is recognized as a rich source of proinflammatory mediators that may directly contribute to vascular injury, insulin resistance, and atherogenesis. Many studies have shown that adiponectin has antiatherogenic and anti-inflammatory properties. Adiponectin acts not only as a factor increasing insulin sensitivity, and the protective effect may result from its ability to suppress production of proinflammatory cytokines. It negatively regulates the expression of TNF-alpha and C-reactive protein (CRP) in adipose tissue; reduces expression of vascular and intracellular adhesion molecules (VCAM-1, ICAM-1), E-selectin, interleukin-8 (IL-8). Hyperleptinemia has been linked with the development of hypertension and endothelial dysfunction/atherosclerosis, two main pathophysiological conditions associated with cardiovascular disease development. Leptin-mediated increases in sympathetic nervous system activity may be among the principal mechanisms evoking obesity related hypertension. Leptin stimulates the secretion of proinflammatory cytokines, and increases the release of endothelin-1 (ET-1), which may promote hypertension. Increased serum levels of asymmetric dimethylarginine (ADMA), a physiological regulator of the biosynthesis of nitric oxide (NO), promote the process of atherosclerosis, leading to the occurrence of endothelial dysfunction and cardiovascular disease.

Prospective cohort study evaluating risk factors for the development of pasture-associated laminitis in the United Kingdom

BACKGROUND

Certain individuals appear to be predisposed to recurrent pasture-associated laminitis. Previous studies have predominantly investigated risk factors only after disease occurrence.

OBJECTIVES

To investigate risk factors for pasture-associated laminitis prior to disease occurrence.

STUDY DESIGN

Prospective cohort study.

METHODS

Non-laminitic ponies aged ≥7 years were recruited. Body condition score (BCS), height, weight, crest height and thickness were measured and an overnight dexamethasone suppression test performed. Plasma or serum adiponectin, leptin, triglyceride, basal insulin, insulin post-dexamethasone, insulin-like growth factor 1 (IGF-1), IGF binding protein 1 (IGFBP-1), IGFBP-3, C-reactive protein, von Willebrand's factor, soluble E-selectin and P-selectin concentrations were assayed. Follow-up data were obtained from owners annually for 3 years to ascertain occurrences of veterinarian-diagnosed pasture-associated laminitis. Data were analysed by multivariate logistic regression. Receiver operating characteristic (ROC) curves analysis was performed for significant risk factors and cut-off values determined.

RESULTS

A total of 446 animals with a median (interquartile range) age of 15 (10-20) years were recruited. Of these, 50.4% were mares and 49.6% were geldings. The most common breeds were Welsh (36.4%), Shetland (17.0%) and cob (9.4%). Overall, 72.2% of animals were overweight/obese (BCS 7-9/9), 27.3% were of ideal weight (BCS 4-6/9) and 0.5% were underweight (BCS 1-3/9). After 1, 2 and 3 years, respectively, 18 (4.0%), 30 (6.7%) and 44 (9.9%) animals were reported to have had laminitis. Plasma adiponectin, and serum basal (insulin) and (insulin) post-dexamethasone levels were significantly (P ≤ 0.05) associated with laminitis occurrence cumulatively after 1, 2 and 3 years. Use of the area under the ROC curves to distinguish animals that did and did not develop laminitis showed good (basal [insulin] after 1 year), fair (all others) or poor ([insulin] post-dexamethasone) levels of accuracy.

MAIN LIMITATIONS

Animals were evaluated at a single time point and biomarkers were assayed using single assays.

CONCLUSIONS

Risk factors for future laminitis prior to disease occurrence include low plasma adiponectin and high serum basal insulin or insulin post-dexamethasone concentrations.